Disable scan with no adapter available

1 files changed, 41 insertions, 23 deletions

diff --git a/lib/widgets/scan_page.dart b/lib/widgets/scan_page.dart
index dbc64dc..0280889 100644
--- a/lib/widgets/scan_page.dart
+++ b/lib/widgets/scan_page.dart
@@ -96,36 +96,54 @@ class _ScanPageState extends State<ScanPage> {
           children: <Widget>[
             SizedBox(height: 15),
             StreamBuilder(
-              stream: widget.deviceScanner.statusStream,
-              initialData: ScanStatus.idle,
-              builder: (context, asyncSnapshot) {
-                bool isScanning = asyncSnapshot.data == ScanStatus.scanning;
-                return Row(
-                  mainAxisAlignment: MainAxisAlignment.center,
-                  spacing: 15.0,
-                  children: [
-                    ElevatedButton(
-                      onPressed: isScanning ? null : _doScan,
-                      child: isScanning
-                          ? Text("Scanning...")
-                          : Text("Start scan"),
-                    ),
-                    ElevatedButton(
-                      onPressed: (selectedDevice == null || isScanning)
-                          ? null
-                          : _doConnect,
-                      child: Text("Connect"),
-                    ),
-                  ],
+              stream: widget.deviceScanner.availabilityStream,
+              builder: (saCtx, scanAvailability) {
+                return StreamBuilder(
+                  stream: widget.deviceScanner.statusStream,
+                  initialData: ScanStatus.idle,
+                  builder: (ssCtx, scanStatus) {
+                    final bool isScanning =
+                        scanStatus.data == ScanStatus.scanning;
+                    final bool scanAvailable =
+                        scanAvailability.data == ScanAvailability.available;
+                    final bool allowConnect =
+                        selectedDevice == null || isScanning || !scanAvailable;
+
+                    Text scanBtn;
+                    if (!scanAvailable) {
+                      scanBtn = Text("No available adapter.");
+                    } else if (isScanning) {
+                      scanBtn = Text("Scanning...");
+                    } else {
+                      scanBtn = Text("Start scan");
+                    }
+
+                    return Row(
+                      mainAxisAlignment: MainAxisAlignment.center,
+                      spacing: 15.0,
+                      children: [
+                        ElevatedButton(
+                          onPressed: isScanning || !scanAvailable
+                              ? null
+                              : _doScan,
+                          child: scanBtn,
+                        ),
+                        ElevatedButton(
+                          onPressed: allowConnect ? null : _doConnect,
+                          child: Text("Connect"),
+                        ),
+                      ],
+                    );
+                  },
                 );
               },
             ),
             StreamBuilder(
               stream: widget.deviceScanner.scanResultsStream,
               initialData: <Device>[],
-              builder: (context, asyncSnapshot) {
+              builder: (srCtx, scanResults) {
                 return DeviceScanSelection(
-                  items: asyncSnapshot.data ?? [],
+                  items: scanResults.data ?? [],
                   onItemSelected: (item) {
                     setState(() => selectedDevice = item);
                   },